Mainly aiming at application to pharmaceuticals for human, in order to improve the effect of pharmaceuticals by drug delivery system (DDS) or by sustained release, studies of nano-encapsulation of drugs are now under way. For example, DDS in which a drug is encapsulated in cyanoacrylate polymer particles is known (Patent Documents 1, 2 and Non-patent Document 1). The present inventor and co-workers also have disclosed a method for producing cyanoacrylate polymer particles with little irregularity in particle diameter, antibiotic-containing particles, and plasmid-containing particles (Patent Documents 3 to 5). In a conventional method for synthesizing polymer particles, a saccharide(s) and/or a polysorbate(s) is(are) made to be present in the polymerization reaction system. These past studies aimed at DDS or sustained release of drugs.
The present inventors then discovered that cyanoacrylate polymer particles per se have an antibacterial activity against Gram-positive bacteria (Patent Document 6). The present inventors also discovered that amino acid-containing cyanoacrylate polymer particles have an anticancer activity and can exert antibacterial activity against various bacteria irrespective of their Gram staining properties (Patent Documents 7 to 9). Nano-sized polymer particles specifically adhere to the surface of bacteria to cause their bacteriolysis. Cyanoacrylate nanoparticles exert antibacterial activity by an action mechanism that is completely different from those of antibiotics, and are therefore effective for multidrug-resistant bacteria such as MRSA and VRE.
On the other hand, effects of nano-sized polymer particles against viruses are not known.